The role of the ISCWSA Error Model Maintenance Group is to define the mathematical framework for modelling the uncertainty in wellbore surveying. This allows different companies to implement a consistent set of algorithms for error modelling. The committee also defines a set of generic, conservative tool-codes for use when specific service provider tool-codes are not available.
Join the Error Model Sub-committee by contacting Marc Willerth who has taken over the lead from Andy McGregor.
Technical details of the error model may be found on the Model Documentation page.
There have been several revisions of the error model framework. In October 2019, we agreed the content of revision 5.
In general, ISCWSA does not define or supply the detailed magnitudes (error models, tool codes or IPM files) for a particular survey tool. It is our position that the tool provider is the one who is best placed to assess the uncertainty when using their equipment. Therefore users should request tool codes from their tool provider. ISCWSA does not supply, check, certify or in anyway warrant such error models created by tool providers.
However, since the 50th meeting the committee is also responsible for a set of generic tool codes covering many wellbore survey situations.
These models were previously released by the Operators Wellbore Survey Group (OWSG) and are all built upon the mathematical framework defined by this committee. These are simply a set of possible models that are compliant with the ISCWSA framework and are offered for use. These are generic tool codes it is the responsibility of users and service providers to ensure that these models match their application and to apply QA\QC to ensure that survey data matches the assumptions inherent in the models.
The fact that the ISCWSA provides these does not mean that users are forced to use them, that ISCWSA has defined minimum survey requirements, or that tools must be run in this manner. The principle is that any error model applied should correctly match how the tool was used and how it can be expected to perform.
Queries about the work of the error model committee should be addressed to the Sub-Committee chairman Marc Willerth
| Position | Name | Contact |
|---|---|---|
| Chair | Marc WILLERTH | marc.willerth@hpinc.com |